A sofa bed can be converted between a bed configuration and a sofa configuration. One type of sofa beds has three bed sections with mattress portions integrally formed on each of the sections. The mattress portion should be of some thickness to be comfortable when laid upon as a bed section. Collectively, the three sections form the bed when the sofa bed is deployed. An articulating mechanism connects to the sections to guide their movements between the bed and sofa configuration. To this end, sofa beds are bulky compared to contemporary sofa counterparts due to having to stow the multiple bed sections and the articulating mechanism. Additionally, contemporary sofas can be designed with more aesthetic consideration than existing sofa beds as they are not constrained in also having to function as an articulating bed.
The prior art includes a range of designs of such sofa beds. U.S. Pat. No. 2,740,131, for example, discloses a sofa bed where the back section becomes the back portion of the sofa, the forward seating section becomes the seat support portion of the sofa, and the intermediate section is stowed in a generally horizontal position, beneath the forward seating support portion, upside down facing the floor. The stowed configuration is shown in FIG. 2 of the patent.
U.S. Pat. No. 8,011,034 discloses an improvement over the design of U.S. Pat. No. 2,740,131. Additionally, when the articulating mechanism is in the folded position, the sofa bed includes a removable seat and back cushions. However, as shown in FIG. 4, the geometry of the articulating mechanism requires the sofa frame to be of a certain shape in order to accommodate the mechanism's stowage. To this end, the profile of the disclosed sofa bed is box-shaped and bulky.
In addition to being constrained in certain aesthetic appeal, prior art sofa beds of the types described above are not easy to use. The bed sections are often heavy, particularly to a large subset of the population, to lift out of the sofa or to stow back into the sofa frame. The high threshold to articulate the sofa bed is often by design to provide stability to the bed sofa when in the deployed and folded configuration. To this end, the sofa bed is less likely to fold while being laid upon or to unfold without clear actions by the user.
In addition, sofa beds are often complicated to manufacture. The components, including the bed sections and the articulating mechanism, are both bulky. The articulating mechanism comprises a series of metallic linkage components of varying shapes, sizes, and angles, while the sofa sections are made of fabric. Great care is often expended to avoid damaging the fabric portion of the sofa section, in particular, during the assembling of the sofa sections to the articulating mechanism.